ACL RECONSTRUCTION, TOTAL KNEE REPLACEMENT, ACL INJURIES IN SKELETALLY IMMATURE ATHLETES, REVISION ACL CONSIDERATIONS
ACL RECONSTRUCTION, TOTAL KNEE REPLACEMENT, ACL INJURIES IN SKELETALLY IMMATURE ATHLETES, REVISION ACL CONSIDERATIONS
The Anterior Cruciate Ligament (ACL) is a ligament in the center of your knee that becomes damaged when twisted too far, such as in a skiing injury.
ACL Reconstruction is performed using a combination of open surgery and arthroscopy.
Before the ACL reconstruction process begins, your surgeon will examine your knee arthroscopically, and repair any additional damage to the knee, such as a torn meniscus, or worn articular cartilage.
Reconstruction of the ACL begins with a small incision in your leg where small tunnels are drilled in the bone.
Next your new ACL is brought through these tunnels, and then secured. As healing occurs, the bone tunnels fill in to secure the tendon.
There are three methods of creating a replacement ACL. The first uses the patellar tendon, which connects the patella to the tibia.
The middle third of the tendon and a small portion of bone on either end is harvested and used as the new ACL. This is called a patellar tendon autograft, because your own tissue is used.
Another autograft method uses the semitendinosus-gracilis (hamstring) tendons, which connect muscles in the back of the thigh to the lower leg. Two small portions of these tendons are harvested and removed through a small incision in your leg, then they are looped to form a strong new ACL.
The third method of creating a replacement ACL uses an allograft, meaning the tendon comes from a source other than your own body, such as a donated achilles tendon.
Arthritis of the knees can be mechanical (osteoarthritis) in which the surfaces of the knee gradually "wear out". This may be due to either old age, angular deformity, or old fractures. Systemic arthritis such as rheumatoid arthritis or gout affects the synovium (the membrane tissue in the joint that normally lubricates the joint), becomes pathologic and the surface of the joint is destroyed.
In either case when the surface of the joint is worn away, at a certain point in time walking and activities of daily living become very difficult. Standardized treatment such as weight loss, anti-inflammatory medication, braces, orthotics, steroid injections, physical therapy, etc. are all tried and if effective that is fine.
In many cases, however, despite the above non-surgical treatments, functional limitations persist. Most people who are considering knee replacement are limited to walking less than three to six blocks, or less than 15 to 20 minutes. They have difficult time getting up out of a chair. They have rest pain. They are taking anti-inflammatory medication and/or pain medicine on a regular basis and the pain is generally progressive.
It is important to realize that a knee "replacement" is actually just a "resurfacing" of the knee joint. The femur or thigh bone is covered with a metal covering and plastic is placed on the tibia so that instead of irregular arthritic surfaces, one has metal and plastic articulating which produces a smooth non-patent surface. In most cases the undersurface of the knee cap is also replaced with a plastic surface so that this articulates with the femoral surface.
Knee replacements have been done since the early 1970's and our most recent designs appear to have 85% to 90% survival at twenty years. Knee replacement in 1998 are more successful than hip replacements with a lower incidence of revision.
The actual procedure involving knee replacement involves either general or epidural anesthesia with a four to six day hospitalization. The surgery itself takes between 1-1/2 and 2-1/2 hours. In most cases patients donate two units of autologous blood to be used in the postoperative period. Weight-bearing begins immediately the first postoperative day. Patients usually use a walker for a period of one to two weeks, going to crutches and then a cane. People are off all walking aids anywhere from three weeks to two months.
Success rates in knee replacements are approximately 90% with 10% not doing as well. This can be due to either stiffness or ache or swelling in and about the knee. The most significant complications, aside from general medical complications (heart and lung) involve infection of the prosthesis. If this occurs, in some cases the prosthesis can be saved and the patient taken back to the operating room, the knee irrigated with antibiotic irrigation and then be on antibiotics. In some cases if this does not respond, then the entire prosthesis must be taken out and antibodies given for six weeks and then another attempt at re-implantation of the of the prosthesis must occur. In an extremely small percentage of cases, conceivably if the infection could not be controlled, then one is left a knee fusion in which the femur and tibia are fused in one bone.
Activities after knee replacement that should produce no difficulty are simple walking, bicycling, golfing, swimming. The prosthesis is not designed form impact loading sports such as skiing, basketball, racquetball. People have been know to play doubles tennis with bilateral knee replacements
In both the medical and lay press, much has been written about athletic knee injuries in adults. Most of us have at least some familiarity with tears of the anterior cruciate ligament (ACL) and how they affect the season, and sometimes the career of professional, collegiate or local high school athletes. Newspapers often quote team physicians and include reports of MRI results after a professional or other high-profile athlete suffers a knee injury. Many ski vacations have been cut short by a bad fall and subsequent visit to an orthopedic surgeon back home, resulting in a diagnosis of ACL tear. Fortunately, the orthopedic community has extensive collective experience in treating this problem – patterns of injury are understood, the natural history is well defined and surgical techniques continue to be perfected. Despite some ongoing controversy regarding the technical aspects of the surgical reconstruction, most patients who suffer an ACL injury have a predictable outcome from surgery or learn to maximize their function without surgery.
Only recently, however, have surgeons begun to fully understand the nature of ACL injuries in skeletally immature athletes. Specialized study of ligament injuries in children is necessary because of the unique biology of growing bones and ligaments. Longitudinal growth in the child takes place at the ends of the long bones, with particularly rapid growth occurring around the knee at the end of the femur (thigh bone) and top of the tibia (shin bone). Growth plates (where growth occurs) are comprised of a sliver of specialized cartilage through a cross section of these bones near each joint. The bones literally increase in length and grow away from these areas. ACL surgery presents unique issues in adolescent or skeletally immature athletes because the reconstructive surgery involves drilling tunnels across the growth plates and placing a graft (replacement ligament) into the knee joint through these tunnels.
In adults, who have completed skeletal growth, the passage of the graft does not affect the growth plates adversely as they have already closed and growth has ended. In children, however, this part of the surgery can theoretically injure the growth plates, resulting in a shortened or angulated leg compared to the opposite limb that continues to grow normally. The degree of the deformity depends upon the extent of injury to the growth plate and the amount of growth remaining. In other words, if damage to the growth plate occurs, younger patients are at risk for greater degrees of growth disturbance.
Your child’s orthopedic surgeon will take all of these biologic issues into consideration when counseling him or her on treatment options for an injured knee. Several variations on traditional surgical techniques have been devised in an attempt to minimize disruption of the growth plates during surgery. While no surgery is risk-free, choosing the proper technique to reconstruct the ligament at the appropriate time in the child’s growth curve should lead to predictable results in treating ACL injuries.
A history of a twisting injury associated with an audible “pop” followed by swelling of the knee raises suspicion for a ligament tear. When visiting an orthopedic surgeon for a knee injury, your young athlete should expect a thorough examination of the knee followed by x-rays and, if there is suspicion of an ACL tear, a referral for an MRI study to verify the diagnosis.
Once the diagnosis is confirmed, then the process of decision-making begins. It is very important that the treating physician have significant experience in treating ACL injuries in immature athletes. As outlined above, your physician will help you to assess the risks and benefits of the various treatment options for a torn ACL. The major decision point revolves around conservative treatment, including supportive exercise and activity modification, versus surgical reconstruction. This is a decision that must be made by the patient, parents and physician together as the treatment depends very much on the young athlete’s ago, biology, goals, motivation and education
Injuries of the anterior cruciate ligament (ACL) are thought to occur as frequently as 1 in 3000 people. The mechanism of injury is often a non-contact twisting of the knee that results in immediate pain and swelling. It has been estimated that there are over 100,000 ACL reconstructions performed each year in the United States and this number is reported to be increasing. ACL reconstruction surgery has a success rate of 80-90%. However, that leaves a substantial number of patients that have unsatisfactory results. Eight percent of these poor results are thought to be due to knee instability or re-rupture of the ACL graft. Failure of an ACL reconstruction is often hard to describe. The patient can have complaints of knee instability, pain, stiffness, or the inability to return to desired activities. Treatment for failed ACLs is complex and technically challenging, and the results of revision ACL surgery are not as good a primary ACL reconstruction. It is therefore important to follow a specific approach to evaluate, diagnose, and treat potential revision ACL cases.
There is no specific injury that leads to failure; however, the time failure occurred after surgery can help determine the cause of failure. Failures that occur within the first 6 months can be due to poor surgical technique, failure of graft healing, or too aggressive rehabilitation. Failures that occur after 1 year are usually due to another injury. Other factors that can lead to an unsatisfactory outcome are injury to other knee structures or leg alignment. Other structures injured in the knee may be the meniscus (lateral or medial) which acts as a shock absorber, or the cartilage on the ends of the femur (thigh bone) or the tibia (shin bone).
These injuries need to be evaluated and may need to be addressed at the time of repeat surgery if necessary.
An evaluation for a failed ACL should include a thorough history and physical exam to determine the level of recovery and potential cause of failure. Repeat x-rays that include the entire leg, an MRI that may require a contrast injection for better detail, and possibly a CT scan or bone scan will often be required to determine causes of failure, other injuries, and plan for potential revision surgery. Issues to consider include injuries to other structures as previously described, but also location and size of the previous tunnels, types of graft material used, and fixation devices used to secure the graft. If it is determined that a revision ACL reconstruction is required, then a thorough discussion with the orthopedic surgeon should explain the plan, graft options, and other surgeries that may be required.
Treatment for a failed ACL may require a staged approach with other surgeries done first before the revision ACL surgery. Some other surgeries may include a knee scope to remove the old screws or other fixation devices and possibly bone grafting of the tunnels to allow new tunnels to be drilled later. Other surgeries may require a “realignment” of the knee to allow a revision ACL a chance to be successful. If these other surgeries are required, the revision ACL surgery may not be able to be performed for up to 6 months later.
Graft choices will be discussed and the type of graft chosen will depend on many issues, including tunnel placement, previous grafts used, or requirement for other surgeries. Options for using the patient’s own ligaments (autografts) include the patellar tendon, hamstring tendons or quadriceps tendon. Options for using donated ligaments (allografts) include Achilles tendons, patellar tendons, and tibialis tendons. All of the tissue processing companies are required to abide by strict standards and techniques to minimize risks of disease transmission. If the guidelines from the American Association of Tissue Banks are followed, the risk of disease transmission is estimated to be 1 per 1,000,000 cases. Many studies have been performed that have shown safe and successful use of allograft ligaments for ACL reconstruction. However, the tendon chosen will often depend on specific issues unique to each patient.
The rehabilitation for a revision ACL reconstruction is similar to the initial reconstruction, but may be more lengthy and less aggressive. It must be explained to patients that the results are less predictable than their initial surgery and it is very important that they followed the staged rehabilitation. Each rehabilitation program will be individualized to match the type of revision surgery, graft fixation, and additional surgery that the patient had. Weight bearing is often protected longer and return to sports is withheld compared to primary ACL reconstruction.
Revision ACL reconstruction is a complex undertaking and is recommended for patients that have instability both subjectively and objectively. The cause of the failure must be investigated carefully and will involved several studies that have been performed in the past. Preoperative planning is very important and may identify staged surgeries that will be performed before the revision ACL. The patient must understand that the results of revision ACL reconstructions are not as good as the initial ACL and the goal of the revision is to allow the patient to do their activities of daily living instead of return to competitive athletics. The patient should have realistic goals and understand all of the issues, but can be reassured that with the proper evaluation, treatment, and rehabilitation, a successful outcome can be expected in most cases.